1. Field of the Invention
The present invention relates to a method of treating the inner surface of a metallic mold for molding resin products and more specifically to a method of treating the inner surface of a metallic mold suitable for use in molding artificial leather formed with a leather like pattern.
2. Description of the Prior Art
To manufacture artificial (resin) leather, it is necessary to form a leather like pattern on the surface of the resin leather. Therefore, a predetermined pattern is formed on the inner surface of a metallic mold for manufacturing resin leather. In the prior-art method of treating a metallic mold, a leather like pattern is usually formed on the inner surface of a metallic mold simply in accordance with only etching treatment as disclosed in "METALLIC SURFACE TECHNICAL MANUAL" (2nd Edition) edited by Japanese Metallic Surface Technical Association and published by NIKKAN KOGYO SHINBUN Co., Ltd. on Dec. 25, 1977, for instance. After etching treatment in the prior-art method, the metallic mold is finished by performing various treatments such as cleaning, anticorrosion treatment, antidiscoloration treatment, heat treatment, etc.
In the prior-art method of forming a leather like pattern on the inner surface of a metallic mold in accordance with only etching treatment, there exists a problem in that since the surface condition are uniform all over the inner surface of a metallic mold, it is impossible to provide real leather like feeling or touch for the surface of the molded artificial resin leather.